1. Field of the Invention
The present invention relates generally to electrical switching apparatus and, more particularly, to rocker switches. The invention also relates to actuators for rocker switches.
2. Background Information
Rocker switches are generally old and well known in the art. As shown in FIG. 1, a rocker switch 2 generally includes a housing 4 having a first or upper (from the perspective of FIG. 1) portion 6, and a second or lower (from the perspective of FIG. 1) portion 8. The housing 4 is typically made from a non-conductive material, such as a heat-resistant plastic, and is structured to define a cavity 10 therein. Typically, the upper portion 6 of the housing 4 contains an actuator, such the pivotal button or operating member 12, which can be actuated from the exterior of the housing 4. The lower portion 8 of the housing 4 contains a conventional mechanism for conveying a signal that the switch 2 has been actuated. Specifically, when the operating member 12 is actuated, at least one moveable contact 14,16 is moved into or out of engagement with a corresponding stationary contact 18,20 (e.g., moveable contact 14 is engaging stationary contact 18). The stationary contacts 18,20 are in electrical communication with one or more terminals 22,24,26 (e.g., stationary contact 18 is in electrical communication with load terminal 22) at the base 28 of the housing 4. Typically, three terminals are present, with first and third terminals 22,26 being disposed proximate the ends of the switch 2 and comprising load terminals, and a second, middle terminal 24 being a line terminal. Each of the terminals 22,24,26 extends from outside the housing 4 into the cavity 10.
The lower portion 8 of the housing 4 also requires another mechanism or subassembly 30 structured to provide a resistance force in order to create a tactile, “snap” feel of the operating member 12 and to facilitate the switching action when adequate force is applied to the operating member 12. This mechanism is commonly referred to as an “over-center” mechanism 30. Known over-center mechanisms (e.g., 30) typically comprise a separate sub-assembly having a shaped member 32 and a spring member 34, although other configurations (not shown) are possible. The shaped member is usually a deflective conductor 32 which has a specific profile and is structured to pivot and engage the stationary contacts 18,20 electrically connected to the terminals 22,26. The profile of the deflective conductor 32 dictates the operating characteristics (e.g., without limitation, type of action, such as, momentary or sustained; number and location of positions of the operating member; operating forces) of the rocker switch 2. The spring member 34 typically biases a plunger 36 against the deflective conductor 32 which causes the operating member 12 to, for example, be in either of two positions which are on either side of a centered point or position. Of course, it will be understood that the operating member 12 may have more than two positions. The force required to move the operating member 12 from one position to the other position decreases suddenly once the center point of the mechanism 30 has been passed. Hence, the component's “over-center” name. In this manner, the desired snap-type tactile feedback is provided.
However, the foregoing structures take up significant space within the rocker switch 2, particularly in the lower portion 8 of the housing 4. This requires the switch to have considerable depth 38 which is undesirable in many applications where mounting space is limited (e.g. without limitation, in the instrument panel of an airplane).
There is, therefore, room for improvement in rocker switches and in actuators therefor.